Hitherto, as a method for coating a film member with a functional film, there have been known dry coating, wet coating, laminate coating and other methods. Out of these methods, wet coating has been used, which makes use of a slot die, a Meyer bar, a gravure or some other that can make coating at low costs.
Out of wet coating species, gravure coating has been used in various fields, the coating being excellent in producing performance, maintenance performance, or handleability. Gravure coating is a method of filling a coating fluid into a vessel called a pan, bringing the coating fluid into contact with a gravure roll having a grooved surface while rotating the roll to transfer the coating fluid held on the surface to a film member.
In the meantime, depending on a product to be coated, it may be unnecessary to coat the entire surface of the product to be coated with a coating fluid in accordance with various purposes. For example, there may be a case where a region on which no coating fluid is coated is formed in a film member to have a predetermined width in the running direction of the film member. Patent Document 1 discloses the use of a gravure roll in which gravure grooves are not formed at sites corresponding to a region on which no coating fluid is coated. However, a coating fluid may unfavorably move along an inclination direction of the gravure grooves so that the coating fluid may deposit between a coated region and an uncoated region. Thus, therein, a portion large in film thickness may be generated (high-edge phenomenon). When the high-edge phenomenon is generated, wrinkles or others are generated in the film member, which is a wound member, so that the member may not be usable for a product or the next step. Thus, a demand for techniques for restraining the generation of the high-edge phenomenon has been increased.
In response to this demand, for example, Patent Document 2 discloses a bar coating device for coating a long flexible support that is continuously running (hereinafter referred to as a web) with a coating liquid. The bar coating device has a columnar coating bar having an outer circumferential surface in which a spiral groove is formed. As the coating bar, a bar is used in which portions corresponding to outsides of both end portions in the width direction of the web are smaller in depth than a portion corresponding to the inside of both of the end portions in the width direction of the web.